MORE ABOUT READ(6)

GFRAZIER at AUSVM6.VNET.IBM.COM GFRAZIER at AUSVM6.VNET.IBM.COM
Mon Aug 19 06:37:37 PDT 1996


* From the SCSI Reflector, posted by:
* GFRAZIER at AUSVM6.VNET.IBM.COM
*
Thank you, Ed, for your note about READ(6). One thing you wrote, however,
makes the wrong conclusion. You said:

>     ... More likely any presently
>shipping host already requires SCSI-2, and certainly new hosts should.
>If so, the host should use read(10) always instead of read(6).  The
>only reason to use read(6) is to support scsi-1 disk drives. ....

SCSI-2 requires BOTH read(6) AND read(10). Therefore a SCSI-2 host would
have used read(6) to guarantee compatibility with both SCSI-1 AND SCSI-2.
The host would NOT have needed read(10) as you concluded.

We have no problem with using read(10) on all FUTURE systems, but it is
those customers with SCSI-2 ROM using Read(6) which concern us. We'll have
to tell those customers that they no longer can be sure that a SCSI-3 drive
will work if they upgrade their system. ..UNLESS read(6) again becomes
mandatory.

Thank you.
Giles Frazier
IBM Austin
gfrazier at austin.ibm.com




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